Lock-stitch sewing machine



Feb. 18, 1941. E, KUHN 2,232,329

LOCK-STITCH SEWING MACHINE Filed Sept. 2, 1957 9 Sheets-Sheet 1 /nventor': 445i);

Fb. 18, 1941. E. KUHN LOCK-STITCH SEWING mcnma 9 Sheets-Sheet 2 Filed Sept. 2, 1937 Feb. 18, 1941.

E. KUHN LOCK-STITCH SEWING MACHINE 9 Sheets-Sheet Filed Sept. 2, 1937 /nventor':

E. KUHN' Fiied Sept. 2, 1937 9 Sheets-Sheet 4 Feb. 18, 1941.

LOCK-STITCH SEWING moans L mjllllli lj f Feb.'18, 1941. U N 2,232,329

LOCK-STITCH mime momma I Filed Sept. .2, 1937 9 shets smat s mus/ :0

Feb. 18, 1941. r v E, u N 2,232,329

LOCK-STITCH sawme momma 4 ,7

Filed Sept. 2, 19s? 9 Sheets-Sheet s F Y a 154 2 I65 I I J Feb. 18, 1941. E. KUHN LOCK-STITCH SEWING MACHINE 9 Sheets-Sheet 7 7 Filed Sept. 2, 19s"! illlf Feb. 18,1941. KUHN I 2,232,329

LOCK-STITCH snwme momma Filed Sept. 2, 1957 9 Sheets-SheetB Fig. 1+. Fig.1.;

19/ H ii I ah /nvento/ Feb. 18, 1941. l E. KUHN 2,232,329

I LOCK-STITCH SEWING MACHIiE Filed Sept. 2, 1937 9 Sheets-Sheet 9 itated. Finally, owing to the novel passing of the ace -P 1 194i Ewald the firm Nollesche Wei-kc, Komm. Ges., Weisseni'els, Germany Application September 2, 1937, Serial No. 162,215 In Germany June 8, 1935 The present invention relates to a lock-stitch sewing machine which is equipped with a horn which contains'the thread feeder and the whirl and serves as a support for the work piece and is principally intended for and shoes. construction of such machines, to accelerate their operation and to reduce the-danger of the premature wearing out of the movable parts.

In the case of the known-machines which are equipped with a horn, the parts that lie within the horn are coupled with their drive which lies outsidethe horn by means of intermediate gearing which have large dimensions and, consequently, a great weight and therefore, owing to their inertia resistances and frictional resistances, have a disturbing influence on the running and, chiefly, on the starting and stopping of the machine. According to my invention, this disadvantage is avoided by virtue of the fact that an intermediate shaft, which is connected to the whirl-driving shaft that lies within the horn, is led past the bearing places for the rotary movement of the horn and through the whole horn-carrier and comes into driving connection only beneath the horn-carrier with a pinion which is arranged so as to be rotatable on the horn-carrier-and concentrically with its axle and on which the drive which lies outside the horn works directly.

In this way, there is produced-considerable reduction of the weight, of the dimensions and of; the frictional and inertia resistances of the intermediate means provided between the whirl-driving shaft and its drive that lies outside the horn, so thatthe machine can be started and stopped more easily and rapidly than hitherto and is thus especially suitable for rapid running. Furthermore,

it is in this way rendered possible to give the horn a considerably-slenderer shape than has been the case in the known constructions, so that the put-.

ting :onand taking off of high-legged boots is facilintermediate shaft through the hom carrier, there is also obtained the advantage that the rod guide.

which-is provided in the horn-carrier and surrounds the thread, .can be heated more effectively than hitherto. The .rod guide is exposed in an advantageous manner for the direct placing of the heating device thereon, so that the guide canbe heated directly and a very short heating time is necessary and it is possible to put the machine rapidly into working order, p

Advantageously, there are provided as operating linkages for the thread-feeder and the thread clamp two slide rods which are slidably mounted the sewing of boots It has as its object to simplify the in longitudinal'grooves that are arran in the de forming the axle of the horn. These slide rods have, as compared with the known tubes that are concentric with the axle ofthe horn, a smaller weight, smaller mass resistances and fewer large frictional surfaces in their'guide, so that, in this way, the rapid .running of the machine is favourably influenced still'further. In. addition, they leave a greater part of the rod guide free for the .direct action of the heating device.

Ordinarily, the lock-stitch machines of the kind that come into consideration here are equipped for the bottom thread with a thread brake which co-operates with the thread-feeder roller that is arranged in thehorn and which is controlled in accordance with the sewing operation. In this frequently leads to unallowably great straining of the thread on account of the spring that is necessary for its operation. Consequently, according to the invention, the, pivot pin of the rocking lever which acts on the slide rod of the thread-feeder roller is mounted on an arm which imparts to the rocking lever of the thread-feeder roller an additional movement which takes the place of the work of the auxiliary take-up which is otherwise provided. The control' of the crank arm is advantageously effected with the aid of a cam plate which. is driven from the machine and which'may be provided on theshaft which controls the CD11? pling gearing. The crank arm or the shaft that carries it is advantageously kept in yielding contact with the cam plate by a spring, so that the' shaft can yield on any change that may occur in the thickness of the work piece or on the occurrence of otherirregularities in the work piece. The thread loop which is otherwise yieldingly held by anauxiliary take-up is therefore now received by the thread-feeder. roller itself which is given through the coupling gear, by the crank arm that is controlled by the crank, an additional movement .which approximately corresponds to the movement of the needle. In this way, the result is obtained that, during thesewing operation, the thread-feeder 'rolleralways necessarily releases as muchfthread as the needle "requires for its working. I p

Further features of the invention are involved in the drive of the needle bar and of the shuttle, which features render these parts suitable'for' a running of the machine that is as rapid as possible.

For the purpose of raising and lowering the needle bar, thereis provided, according to the invention, a toggle-lever gearing which receives its drive from a uniformly rotating crank. The'toggle-lever movementof this gearing is of especial advantage because, on account of the passage of the levers through their stretched position, which passage is effected in the bottom position of the needle bar, the needle'is given a comparatively long stoppage in its bottom end position, so that the time for insertion of the thread into the hook of the needle, which time is otherwise short in thecase of rapidly rimning machines, is extended. In addition, sucha gearing involves the advantage that, even in the case of thick strong leather material, the forces that act against the needle are transmitted to the parts of the drive only to an inconsiderable extent. For the mm of increasing also the period of stoppage of the needle in its top position, the rocking lever of the to glelever gearing, which rocking lever comes into engagementwith the driving crank, may be equipped with an arcuate slot which runs concentrically with the axle of the driving crank for a part of its length that corresponds to about the highest position of the needle, so that the crank pin does not produce any movement of the gearing when in the part concerned of its path.

The movement of the shuttle is, as a rule, effected in the case of the known machines by eccentric cams or other reciprocating p rts which, on the change of the direction of movement, requiregreat accelerating forces and cause sudden strains in the gearing. These disadvantages are especially in evidence in thecase of rapidly running machines. For the purpose of remedying this defect also, there is employed, according to the invention, for driving the shuttle actuator, a uniformly rotating crank which acts on an arc crank which is connected to the stand of the machine by a link and carries out, with its thrust tioniof the movementeof the shuttle toithe move merit of the other-working'parts of the machine. The subject matter of the invention is repre-.

sented by examples of embodiment in the accom- I panying drawings, of which 1'18. 1 is a side elevation of the machine;

Fig. 2 is a partial front elevation and Figs. 3 and 4 are two side elevations of the top part of the machine; 1

Figs. 5 and 6 are respectively a rear elevation and a front elevation of the drive of the shuttle; Fig. 7 is a section through the horn and the saddle mounting of the horn;

Figs. 8 and 9 are respectively a front elevation and side elevation of the driving parts for the thread feeder and the thread brake; parts of each figure being shown in section;

Fig. 10 is a plan of the driving parts for the thread feeder,

Figs. 11 to 13 are respectively a front elevation,

a plan partly in section and a longitudinal section of the casing of the shuttle; and

Figs. 14 to 19 show two further embodiments of the driving parts for the thread feeder.

The machine represented in the drawings is driven by an electromotor, the belt pulleys ll of which are connected by bolts (not shown), with the counter-pulleys It on the upper shaft 2 thatnected with the shaft lll'l' (Fig; 7) through a corresponding bevel-wheel gearing. The drive of the parts working in the horn I33 is derived from this shaft Ill. The crank plate I, which is fixed on the upper shaft 2, engages, by means of its crank pin 4, in the arcuate slot 5. of a rocking lever I which is rockably mounted on the axle 1. The rocking lever 6 is connected by the intermediate member I and the bolts 8 and III with a fur- .ther rocking lever II which is mounted on the stationary bolt l2 and carries a rotatable sliding block II on its free end. The flat sliding surfaces of the block ll engage in a corresponding groove 14 in the needle bar IS, the bottom end of whichrhas a longitudinal slot I6 and a bore in which the needle I! is fixed with aid of the binding screw II. The needle bar li'iscarried in the bearings II and 20 in the upper part of the machine so as to be slidable in the vertical direction.

The rocking movements of the lever 6, which are produced by the rotating crank pin 4, are transmitted by the intermediate member 9 to the rocking lever I l which, acting through the sliding block l2, effects the up and down movement of the needle bar I! which is secured against rotation. During the passage of the hinge bolt 8 through the straight line connecting the bolts 1 and Ill, there is produced the temporary stoppage of the needle II in itslowest position, which stoppage is necessary for the introduction of the bottom thread into the hook of the needle. 4

The arcuate slot in the rocking lever O, which slot receives the crank pin 4, is formed in such a manner that its part which corresponds to the upper position of the needle bar l5 runs concentrically with the shaft 2. Consequently, the crank pin 4 does not impart any rotary movement to the rocking lever 8 during a definite part of its path, so that the needle is given a comparatively long st ppag in the top end position, with the result that the pulling of the thread loop into the work piece is favoured.

. The driving of the feed is eflected from the two steel cam plates 2| and 22 (Fig. 3) which are mounted on the upper shaft 2 and which act on the bell-crank lever ll (Figs. 3 and 4). This bell-crank lever 22 is rockably mounted on the axle I on the upper part of the machine and carries on its pins 2| and 24 the rotatable rollers 22 and 33, of which the roller 32 runs on the cam plate 22 and the roller 22 runs on the cam plate 2|. Since the plate 2|v represents the counteron the rotation of the upper shaft 2, positively cam to the plate 22, the bell-crank lever 20 is,.

driven in accordance with the shapes of the cams.

Rigidly connected with the bell-crank lever 22 is the arm 2! (Fig. 4) which has an arcuate slide link 36 on its free end. The sliding block 21,

which is displaceable in this arcuate slide link a 20, is connected by the hinge bolt 38, the intermediate member 29 and the bolt ill to the forked head ll (Fig. 3) of the rocking lever 42 which ber 44 leads to is mounted on the stationary pin 41. From the pin 48 on the head piece 4| an intermediate memthe pin 45 on the lever 48, the pivot pin 480i which is mounted on theend of the lever 49 which is fixed on the axle I88 that is mounted in the body I of'the machine. The

bottom end 46' of the lever 46is hinged by the pin 50 to the intermediate member II, the free end 52 of which surrounds a cylindrical projection on the feed lever 53. This feed lever 88 is formed with slots 54 and 55 which cooperate with pins 56 and 51 on the presser foot bar 58 which is designed to be raised and lowered. The feedpoint holder 59 is hingedly connected to the pin 60 of the feed lever 53, carries the feed point 8| and is pulled to the projection 68 on the feed lever by the spring 62. On the transmission of the movements of the bell-crank lever 88, which,

movements are caused by the cam plates ,2I and'22, to the feedpoint 61, the parts 44, "and 49 form a hinged quadrangle which, on the raising and lowering of the presser footbar 58, carries the pin 50 parallel to the direction of movements of the presser foot bar, so that, even at diflerent vertical positions, the feed point keeps its lateral position in relation to the presser foot bar.

For the purpose of shifting the feed point, the

- sliding'block can be displaced in the arcuate slide link 36, at the centre of curvature of which the pin 40 lies. In this way, the effective length of the lever 35 which rocks about the axle 1 and, consequently, the path of the feed point 6I also are altered. For this purpose, there is hingedly connected to the pin 64 of the intermediate member 39 an intermediate member or link 65 which isconnected by the pin 66 with the adjusting lever 61 that is rockable about the pin 12. The hinge bolt 10 of the lever 61 carries a guide 69 in which rests the set screw 68 whichis provided with a hand wheel 1|. The free end of the set screw 68 engages in the small circular member 13 which is mounted in the body I of the machine. The a rotation of the screw, 66 with the aid of the hand wheel 1I produces a rocking of the lever 61 about the pin 12 and, through the intermediate lever 65, a corresponding rocking of the intermediate I member 39, the block 31 of which is, in this way displaced in the arcuate slide link.36. The parts 65, 39 and 40 are pivotally interconnected in square or rectangular outline which serves for guiding the sliding block 31 in its particular setting in relation to the lever 35.

The shuttle is, in the case of the machine represented in the drawings, driven from a uniformly rotating crank 14 on the upper shaft 2. The crank pin 14 is embraced by a three-armed crank 15 which is connected by the bolt 16 with a link 11 that rocks about the stationary bolt 18. The shaft 19 of the shuttle picker is mounted in the upper part of the machine and carries a slide link 80, in the cam groove 8| (Fig. of which the follower 82 of the arc crank 15 engages. Owing to this arrangement, the follower 82 of the arc, crank 15 describes, on the rotation of 'the 82 causes a comparatively long stoppage of 'the shuttle during this rotation, so that the movement of the shuttle and the movements of the remainin: parts which serve for forming the stitches can be favourably adapted to each other. In addition owing to the derivation of the movement of the shuttle from the uniformly rotating crank pin with the aid of the coupling gearing, the great accelerations and sudden strains of the driving parts, which occur in other shuttle drives, are avoided. thatthe shuttle drive works considerably more steadily and is especially suitable for rapid nmning and is less exposed to the danger of breakages of gearing and other disturbances.

The end of the shaft 19 remote from the slide link 88 has a splined connection at 88 with the hub of a bevel wheel 84. Permanently engaging with the bevel wheel 84 is the bevel wheel 85 which is rigidly connected by an intermediate shaft 81 with the shuttle picker 86. Owing to the arrangement of the longitudinal grooves 83 on the shaftlt and the corresponding formation of the wheel 84, this bevel wheel can be displaced together with the casing of the looper transversely to the direction of sewing and out of reach of the needle, as will'hereinafter be more fully described. V

The raising and lowering of the presser foot 9| is effected by the lever 49 which is fixed on the axle I88 and on the pin 48 of which there is fitted a sliding block I04 which engages in a corresponding groove in the presser-foot bar 58. The helical spring 82, which is provided on the axle I03, tends to rock the lever 49 in the direction of lowering the presser-foot bar 58. For the purpose of raising the presser-foot bar in opposition to the action of the spring 92, there is employed the lever I02 (Fig. 3) which is fixed to the axle I03 and which carries at its top end a clamping segment 93. The cam 98 on the upper shaft 2, on being rotated, rocks the lever 96 which carries the roller 91 and from which the fixed connection between the levers IN and I02 is effected through the clamping jaws 94. The roller 99, which runs on the cam I00, then causes an always equal lifting of the presser foot, even in the case of different thicknesses of leather, by the rotation of the axle I08 and the rocking of the lever 49. when the machine is at rest, the presser foot may be raised by a special lever I05 which is to be operated wheel gears.

The drive of the whirl is effected with the aid of the bevel wheels I63 and I64 that are driven by the shaft I01. The bevel wheel I64 is-rigidly connected with the spur wheel I65 which engages in a further spur wheel I66 which surrounds the rod guide I25 like a socket and is arranged be-.

neath the horn-carrier I32 and which, in its turn, meshes with the spur wheel I61 that is fixed on the intermediate shaft I66. This intermediate shaft I68 is passed through the whole horn-carrier I32 eccentrically to the axis of rotation of the horn and is connected by a universal joint I69 with the shaft I which drives the whirl in the-known manner.

The drive of the thread feeder is derived from the shaft I01 (Figs. '1 to 10) in the following manner:

The'crank pin I09 onthe crank bush I08, which is rigidly arranged on the end of the shaft I01, is embraced by a coupling I I0 which, at the other end,'is hinged by the pin I I I to the rocking lever II2 that ismounted on the pin II3. 'Thepin H3 is carried by an adjusting member I I4 which is adjustable on the stand II5 oi the machine with the aid of the screws H3 and the slots H1. The

5 roller .I I5, which is mounted on the pin II3 of the coupling III engages in the slot I23 in a rocking lever I2I, the pivot pin I22 of which is mounted on an arm I23 which is rigidly arranged in the stand I I5 of the machine. The end or the rocking lever I2I which projects beyond the slot I23 carries a rotatable sliding block I24 which engages in the groovein a socket ring I23. The socket ring I23 is slidably fitted on the vertical rod guide I25 and is connected to the slide rod I21 by means of screws I23, the upper endof which slide rod, that carries the thread-feeder roller I25, projects into the horn I33.

The horn I33 is connected to the horn-carrier I32 which rests on ball bearings so as to be easily rotatable in the bearing I3I of the stand II5 of the machine. In the horn-carrier I32 there is also fixed at I34 the rod guide I which is provided with a groove I25 (Fig. 10) for receiving the slide rod I21 and takes part in the rotation of 25 the horn and of the horn-carrier. The sleeve I33, which is puton the upfier end of the rod guide I25 surrounds and guides the slide rod I21. The stroke of the slide rod I21 and, consequently, of the thread-feeder roller I25 can be altered by shifting the adjusting member I I4 that carries the pivot pin II3 for the rocking lever II2. In this way, there are altered the length of the curve described by the pin II3, the stroke of the lever I2I and, consequently, also the path traversed by 85 the thread-feeder roller I23.

Above the thread-feeder roller I23, there is mounted so as to be stationarily rotatable in the horn I33 a clamp roller I42 on which a clamp slide I43 bears under the action of the spring I 0 that is adjustable by the screw I45. The slide I43 slides in the guide I44 which receives the spring I45 and the screw I43 and which is hingedly mounted at I41 in the horn I33. For the purpose of raising the slide I43,,there is employed 5 the slide rod I51 which is slidably mounted in the groove I25" (Fig. 10) in the rod guide I25 and the top projection I51 of which engages below the clamp slide I43 and the bottom end of which is connected to the socket ring I53 that likewise slides on the rod guide I25. The slide rods I51 and I21 are, on their external surface, rounded in accordance with the bore of the socket rings I23, I53 and the guiding sleeve I30.

The drive of the slide rod I51 is derived from thejcam plate I43 that is mounted on the crank bush I03 ofthe horizontal shaft I31. For this purpose, there is providjed in the extension I45 of the bearing I3I of the hom-carrier a pin I50 which carries a lever that consists of the arms ISI and I5I'. The lever arm I5I, which carries a roller I52 on its pin I53, is kept in permanent contact withthe cam I43 by the spring I54. The other lever arm I5I' carries a sliding block I55 which engages in the groove in the socket ring 55 I53 which is connected to the slide rod I51, so that the rockings of the lever I5I and I5I', which are produced on the rotation of the cam I43, eifect a raising and lowering of the slide rod I51, the end I31 of which then, in turn, lifts the clamp 10' slide I43, in opposition to the action of the spring I45, for the pinpose of releasing the thread. The vertical position of the projection I51 can be varied within certain limits by means of the screw I53 that is provided between the lever arms I5I and I5I'.

Theiittinginandtakingoutoftherods I21 and I51 is facilitated by the hinge-like mounting of the clamp-slide guide I44. Thus, when the guide I44 is folded upwards about the hinge I41, then, after detaching the socket rings and the roller 5 I42, the rods I21 and I51 can be readily pulledupwards out of the horn. After fitting these parts in, the guide I44 is again folded back downwards and is locked in this position. 1

The thread coming from the stock of yarn runs 10 by way of a thread brake I35 into the wax pot I33 and, from there, passes over the guide roller I31 to the pitch-stripper I33. From there, it is passed by way of an auxiliary take-up and through the bore in m the rod guide us into the horn m. 15

The auxiliary take-up consists of a lever I30 which is rockable about the pin I55 and through a hole iii in which the thread passes. The lever I30 is operated by a spring I32 in such a manner that the 20 thread always remains drawn taut and lies on the v parts I35 to I33. The tension of the spring I32 is smaller than that of the thread brake I35. On its way through the bore I35, the thread is kept at a uniform temperature by an annular heating 5 member I43 which surrounds a jacketing mem- 2 her I of the rod guide. It then runs over the clamp roller I 42 and the thread-feeder roller I25 and vertically upwards and out through the thread feeder to the tip of the horn. The cov-operation so of the thread-feeder roller I25, which is controlled by the slide rod I21, and the clamping device I42- I43, which is raised by the slide rod I51 gives a reliable measuringand feeding of the thread.

In the case of lock-stitch sewing machines, the shuttle is ordinarily arranged as closely as possible 35 to the needle for the purpose of obtaining a faultless seam. In this way the free space between the tip of the horn and the head piece of the machine is greatly restricted, so that the putting of work pieces on the horn involves difllculties, especially 40 in the sewing of long-legged boots. This disadvantage is avoided by the displaceable mounting of the casing of the shuttle as illustrated in Figs. 11 to 13: Here, the upper part of the machine carries the casing I 53 of the shuttle with the shut- (5 tie I 54 displaceably in a carriage guide I52. Arranged rotatably on a pin I35, which is fixed in the upper part of the machine, is the'adjusting lever I55 on which a pawl lever I53 is mounted so as to be rotatable about the pin I 51. A com- 50 pression spring I55 presses the pawl 205 against a stop piece 20I which is adjustable on the upper part I of the machine with the aid of the screw 252. The lever I53 has, in an extension 203, a slot 203 which serves for guiding the pin 204 which 55' is fixed to the casing I53 of the shuttle. I v

Now, if the shuttle is to be brought into the working position, the pawl lever I5 5 is moved downwards. In this way, the locking of the lever w I53 is released, because the pawl 200 is moved away from the face 20l' of the. stop 20I. Thereupon, the lever I33/I53 is rotated round the pin I55 into the position shown in dot-and-dash lines (Fig. 12), its extension 233 bringing the casing of the shuttle forward, through the pin 204 into the dot-and-dash position in which the set screw 255 meets the'bolt 203 in the head piece. The position of the tip of the shuttle in relation to the needle can be adjusted accurately with the aid of the screw 235. Now, if the pawl lever I53 is released in this position, the pawl 203 is brought by the compression spring I55 behind the face 20I' of the stop 23I and the shuttle is fixed because, on the one hand, the set screw rests on the bolt 203 1g aaeaeae and, on the other hand, the pawl 200 rests on the stop 20I".

The housing of the spool is fixed in the casing of the shuttle by a holding finger 208 which is. rockably mounted on a projection-201 of the casing of the looper and can be locked by the locking lever 2I I. For the purpose of exchanging the spool 209, the casing I93 of-the looper is-brought into the position represented in Fig. 12. By compressing the spring 2 I2 by means of the levers 2" and 2I I, the locking of the holding finger"! is released and the finger 208 can then be brought into the position shown in Fig. 13. A resilient'push button is arranged in the casing I98 of the looper for thepurpose of facilitating the pushing out of the spool. The housing I93 has a bore 2I8 for the reception of the pin 2I4 and the shuttle I94 has an opening 2I8 to receive the pin 2I5. The push button is pushed outwards by the compression spring 2I8. The pin 2I1, which engages in a corresponding slot, serves for limiting the movement of the push button. The pin 2 I4 of the push button is moved inwards for the purpose of pushing out the spool. When this is being done, the pin 2 I 5 comes into action on the end wall of the small spool 209 through a hole 2 l8 provided in the shuttle and pushes the spool 209 and the housingoi the spool out of the shuttle. The spring 2I9 then brings the pinv 2I4/2I5 back into its original position. I

The construction according to Figs. 14 to 16 agrees with the construction according to Figs. 8 to 10 in so far as, in the two cases, the raising and lowering of the slide rod I21, which carries thethread-feeder roller I29; is effected from the rotating shaft I01 through the crank pin I89, the coupling IIO, the rocking lever I I2 and the rock-- ing lever I2I, the sliding block I24 of which engages in the slide. rod I21. Further, in the case of both gearings, the pin I I3 of the rocking lever I I2 is arranged on an adjusting member 4 which is adjustabl'y connected to the stand II5 of the machine with the aid of screws H8 and slots II1 for the purpose of altering the stroke of the slide rod I21.

Now, whereas, according to Figs. 8 to 10, the rocking lever I2I was connected to a rigidarm I28 of the stand of the machine, in the case of the gearing according to Figs. 14 to 16, the pivot pin I22 of the rocking lever is fitted to the crank arm I which is rigidly connected with the shaft III; The shaft I8I is rockably mounted in the stand I I 5 of the machine and carries a lever arm I82 the roller I84 on which bears, under the action of the torsion spring I86, which surrounds the shaft III, on the cam plate I85 which is connected with the shaft I01. The initial tension of the spring I89 can be regulated with the aid of a bush I81 which is rotatable in the stand of the machine and is fixable by a screw I89 and which has on one end a slot I81 for receiving the end I88 of the spring and has,- on its other end, an hexagonal part I88 which serves as a. handle. The set screw I9I, on which the extension I90 of the lever arm I82 can bear, determines one end position of the shaft Ill and, consequently, of the crank arm I80.

On, the upward movement of the thread-feeder roller I29-i. e., on the upward rocking of the lever I2I, the cam roller I84 is locatedon thehigh part of the cam I85. The rocking shaft I8I then receives no movement and the extension T 90 of the leverv I 82 bears on the stop screw I9I. The pulling in of the thread loop, which has just been carried over the shuttle, is eilected positively merely by 75 the coupling drive I09/I2I, since the parts I89 to 5 I84 are kept stationary between the raised part of the cam I85 and the stop I9I and, consequently, the pin I22 remains stationary. The beginning of the downward movement represented in Fig. 14.

0n the upward movement of the thread-feeder roller I28 (Fig. 7) the movement is delayed owing to the fact that the cam roller I84 is moved resiliently into-the depression in the cam I85- Consequently, the pin I22 is moved upwards, the lever I2I is rocked about the pin H8 and the sliding block I24 is moved downwards. However, this relative downward movement of the slidingblock I24 meansonly a delay in the downward movement of the thread-feeder roller which corresponds to the work of the auxiliary take-up otherwise provided. This-movement takes place in the time in which the needle pulls the bottom thread loop out of the piece being sewn.

The cam I85 is arranged in such a manner that there is imparted to the pin I22 and, therefore, to the sliding block I24 and the thread-feeder. roller I29 a movement which corresponds to the upward movement of the needle. I In the sewing. the thread-feeder roller therefore necessarily releases exactly as much thread as the needle pulls out at any moment. If, however, during the sewing, a fairly large variation in the thickness of the piece being sewn occurs, this difference is compensated for in the. stroke of the thread feeder by the ability of the additional gearing to yield resiliently. The spring I88 on shaft I8I-, as shown in Fig. 16, renders it possible for the roller I84 to raise resiliently from the cam disk I85 when the thread tension in roller I29 becomes too great. when the threadfeeder roller yields upwards, the slidingbiock I24 is moved upwards and the cam roller I84 is raised by the cam I85 in opposition to the tension of the spring.

"After the loop has been pulled out by the needle, the cam roller I84 is again moved on the cylindrical part of the cam I85 by the further rotation of the latter and the lever I82 is fixed between the stop I9I and the cam I85.

The additional movement that is effected, from the shaft I8I therefore takes the place of the too slowly working resiliently acting auxiliary of the lever I2I is take-up I50 of the construction according to Figs.

8 to 10. It serves the purpose of releasing the thread in accordance with the movement of the needle in the time in which the needle takes the loop out of the piece being sewn and, further, of resiliently compensating for irregularities owing 'to the alteration of the thickness of the piece being sewn. Notwithstanding this, the pulling in of the thread loop is effected positively and with an adjustable size of stroke of the tread-feeder roller.

Inthe construction according to Figs. 17 to 19, ahigher coupling drive is provided in the driving device forthe slide rod i21 and between the driving crank pin I09 and the lever I2I, which carries the sliding block I24 and rocks about the pin I 22. Here, the crank pin I09 is embraced by an arm of a coupling 220, the other arm of which is connected to the link 222. The link 222 isrockably mounted on a pin 223 that is fixed in the body of themachine. The pin 224 of the coupling 220 is hinged to the coupling 225 which is connected, on the one hand, with the link 228 by the pm 221 and, on the other hand, with the rocking lever m by the ins 221 and 22a and the hinged link 229. If'he link 225 rocks about; the pin 230 which is carried by the adjusting member 23I that is fixed to slots.

Owing to the higher coupling drive of this construction, the result is obtained that the pin 22! of the-coupling 220 describes a cam movement on the movement of thesaiddrive, which coupled curve prolongs the stoppageof the sliding block I24 and, consequently, of the thread-feeder roller I29 in the bottom end position. In this way, the faultless pulling in of the thread on the formation of stitches is favoured. In addition, owing to the mounting of the ge bolt 230 of the link 22' on the adjusting mem r 2", the possibility is here given of carrying o the alteration of stroke of the thread-feeder oller which is to be effected on a variation in the thickness of the work piece, without shifting the top end position of the thread-feeder roller.

In the case of the constructions according to Figs. 8 to 10 and 14 to 16, there is employed, for the purpme of altering the stroke of the threadfeederroller I29, the adjusting member ill to which the link 2 of the coupling is connected. The result of an alteration of the position 0 the adjusting member H4 is, in those cases, th with the alteration of the size of the stroke of the thread-feeder roller, both the top and bottom end positions of the latter are altered. In contradistinction to this, if the adiusting member Ni 01 the construction according to Figs. 17 to 19 is shifted for the purpose of compensating for too great differences in the thickness of the piece being sewn, the pin 230 effects, when the coupling 225 (Fig. 1'7) is in the position whichcorresponds to the top Po ition of the thread-feeder roller, only a rocking of the link about the pin 221 without transmitting a movement to the coupling itself. The top end position of the thread-feeder roller therefore remains unaltered. A movement of the adiusting member upwards produces, when the thread feeder is in the bottom position of rest (Fig. 18), a raised position of the link bolt 221 of the coupling 225, and, consequently, of the rocking lever |2l which is connected with the coupling by the link 22!. The alteration of stroke is therefore efiected solely by shifting the bottom end position of the thread feeder. In this way, a uniformly deep pulling of the thread into the material of the work piece is ensured with every thickness of the work piece.

What I claim is:

l. A lock-stitch sewing machine of the type including a needle bar, shuttle, thread feeder, and a whirl, comprising a horn receiving the thread feeder and whirl, a rotary carrier for the horn, a tubular shaft in the lower end of the rotary carrier, a pinion on the lower end of the tubular shaft, an intermediate shaft journalled in the rotary carrier parallel to and spaced from the axis of the latter, a pinion fixed on the lower end of the intermediate shaft and meshing with the first mentioned pinion, a gear mounted to revolve on a fixed axis parallel to the axis of I 8,289,829 the body of the machine by screws and V grooves to slidably receive the slide rods, the slide rod which operates the thread clamp being controlled by a cam.

3. A construction as defined in claim 1, including a thread clamp, two slide rods as operating linkages for the thread feeder and the thread clamp, a guide forming the axis of the horn with said guide having two longitudinal grooves to slidably receive the slide. rods, the slide rod which operates the"thread clamp being controlled by a cam, the slide rod which controls on the casing to alter the stroke of the thread feeder. a

4. A construction as defined in claim 1, including a thread clamp, two slide rods as operating linkages for the thread feeder and the thread clamp, a guide forming the axis of the horn withsaid guide having two longitudinal grooves to slidably receive the slide rods, the slide rod which operates the thread clamp being controlled by a cam, the cam controlling a bellcrank lever for acting upon the slide rod of the thread clamp, with a set-screw to vary the vertical position of a projection onthe slide rod to engage the thread clamp.

5.'A construction as defined in claim 1, including a thread guiding roller mounted for rotation in a fixed axis of the horn, .a movable thread clamp acting on the thread guiding roller, an elongated slide on which the thread clamp is mounted, means to permit axial movement of the slide in a direction varying froin that of the cluding a thread clamp, two slide rods as operating linkages for the thread feeder and the thread clamp, a guide forming the axis of the horn with said guide having two longitudinal grooves to slidably receive the slide rods, the slide rod which operates the thread clamp being controlled by a cam,

a rocking lever acting on the slide rod of the thread feeder and having a pivot pin, a crank arm on'which the pivot pin is mounted, with the said crank arm rocked in accordance with thetsewing operation to thereby impart to the rocking lever and to the thread feeder an.additional movement to compensate tor the work of the ordinary conventional-auxiliary take-up.

8. A construction as defined in claim 1, including a thread clamp, two slide rods as operating linkages for the thread feeder and the thread clamp, a guide forming the axis ofthe horn with said guide having two longitudinal grooves to slidably receive the slide rods, the slide rod' which operates the thread clamp'being controlled by a cam, a rocking lever. acting on the slide rod of the thread feeder and having a pivot additional movement to compensate for the work of the ordinary conventional auxiliary take-up, a rocking shaft on which the crank arm is pivoted, a second arm for rocking said shaft, and a cam plate for operating the second arm.

9. A construction as defined in claim 1, including a thread clamp, two slide rods as operating linkages for the thread feeder and the thread clamp, a guide forming the axis of the horn with said guide having two longitudinal grooves to slidably receive the slide rods, the slide rod which operates; the threadv clamp being controlled by a cam, a rocking-leyer acting on the slide rod of the thread feeder .and having a pivot pin, a crank arm on which the pivot pin is mounted, with the. said crank arm rocked in accordance with the sewing operation to thereby impart to the rocking lever-Hand to the thread feeder an additional movement to compensate for the work of the ordinary conventional auxiliary take-.up, a rocking-shaft on which the crank arm is pivoted, a second arm for-ilrocking said shaft, and a cam plate for operating the second arm, and an adjustable-spring for pressing the arm yieldingly to the camplate'.

10. A construction as defined in claim 1, including a ,thread clamp, two slide rods as operating linkages for the thread feeder and the thread clamp, a guide forming the axis of the horn with said guide having two longitudinal grooves to slidably receive the slide rods, the slide rod which operates the thread clamp being controlled by a cam, a rocking lever acting on the slide rod of the thread feeder and having a pivot pin, a crank arm on which the pivot pin is mounted, with the said crank arm rocked in accordance with the sewing operation to thereby impart to the rocking lever and to the thread feeder an additional movement to compensate for the work of the ordinary conventional auxiliary take-up, a rocking shaft on which the crank arm is pivoted, a second arm for rocking said shaft, and a cam plate for operating the second arm, and an adjustable spring for pressing the arm yieldingly to the cam plate, the cam plate being provided with a raised part for maintaining the crank arm of the rocking shaft and the pivot pin stationary during the downward movement of the thread feeder, said cam plate having a depressed part acting on the'upward movement of the thread feeder to impart to the rocking lever an additional movement in a direction to delay the normal upward travel of the thread feeder.

11. A lock-stitch sewing machine of the type including a. thread feeder, a whirl, areciprocal needle bar and a; shuttle picker, and means for driving the shuttle picker, including a uniformly rotating crank, a three armed crank connected to the uniformly rotating crank, a link connecting the pivot of the last mentioned crank to the machine, a, follower, the connection compelling the follower to travel in a path approximating an 8'-shaped loop, and a slide link provided with a cam groove and having its axis of rotation in one part of the 8-shaped loop, the follower being engaged in the cam-shaped groove of the link to transmit movement to the shuttle picker.

12. A construction as defined in claim 11, in

eluding a shaft carrying the slide link, means for supporting the shaft for rotation and for axial displacement, a second shaft in splined relation to the first shaft to revolve therewith, a toothed wheel fixed on the second shaft, a shuttle drive including a gear meshing with said toothed wheel, and a carriage in which the shuttle drive is mounted, said carriage being displace- .able transversely of the direction of sewing and supporting the shuttle and the shuttle actuator, and m'eans'to effect movement of said carriage.

13. A construction as defined in claim 1, characterized by having a vertical rod guide provided with a'longitudinal guide groove and having a thread feeder operating rod mounted in said groove and actuating the thread feeder, a'bell crank lever, means to rotate the end ofone arm of the lever through a circular path,'a link havingone end, mounted on a fixed pivot and its other endpivoted to the end of the remaining arm, an operating lever having one end mounted ona pivoted support and its other end operacrank lever, means to rotate the end of one,

arm of the lever through a circular path, a link having one end mounted on a fixed pivot and its other end pivoted to the end of the remaining arm, an operating lever having one end mounted on a pivoted support and its other end operativelyconnected to said operating rod, a second bell crank lever having one arm pivoted to the angle of the first bell crank lever, a link connecting the angle of the second bell crank lever to the operating lever at a point intermediate its ends, an adjustable slide, a link connecting said slide to the remaining arm of the second bell crank lever, and means to secure the slide in adjusted position.

EWALD KiiHN. 

